AFAIK, most boost converters incorporate a diode or some mechanism for ensuring that current flows from the battery to the output. For instance, TPS61030's datasheet says that
This device however uses a special circuit which takes the cathode of the backgate diode of the high-side PMOS and disconnects it from the source when the regulator is not enabled (EN = low).
MPC6140's datasheet says that
With the EN pin pulled low, the output of the MCP1640B is isolated or disconnected from the input by turning off the integrated P-Channel switch and removing the switch bulk diode connection. This removes the DC path that is typical in boost con- verters, which allows the output to be disconnected from the input.
Does that mean if current tries to flow from output, these chips (at least these two?) won't be damaged at all? That is, for instance, there are two possible power sources connected in parallel, boosted to 5V. If only one is hooked up, would the current flowing into the other booster in reverse fry it?
What if both could be hooked up?